Cocoa has three major sets of Objective-C libraries, or frameworks, that comprise its main features and functions:

The Foundation Kit, also known as Foundation, which provides string and value manipulation, containers, iteration, distributed computing, and looping. The Foundation libraries are fundamental tools not related to the graphical user interface (GUI) of OS X.

The Application Kit, also known as the AppKit, contains all the GUI functions.

Core Data, the library that provides an aspect of application development known as object persistence.

The iOS version of Cocoa is called Cocoa Touch. It provides similar functionality as Cocoa, with the addition of functions specific to mobile devices; such as gesture recognition.